The buckle air is a sophisticated art and involves many devices used for adjusting the length of the web-like material, belting or strapping with which it is to be associated. To provide an adjustment means without the use of any moving parts has been previously shown in the patent to C. L. Hastings U.S. Pat. No. 779,279 patented Jan. 3, 1905, and the patent to F. C. Rehm U.S. Pat. No. 1,142,842 patented June 15, 1915.
Devices somewhat related to the Rehm patent are still in use today as adjustment means for lifejackets, backpacks, etc. and involve the physical fastening of one extremity of a web-like material to one end of the buckle and providing adjustment through the use of a pair of parallel bars at the opposite extremity. The Rehm patent is an improvement of Hastings' disclosure and utilizes a downwardly extending lip for impingement on the moveable free end of the web-like material to prevent its slipping from the adjusted position.
There are deficiencies in such a device, however, in that by rotating the device about its fastened end, the adjustment end can be released, either intentionally or by inadvertent pulling on the strap, by a rotation of movement of approximately 35.degree.-45.degree.. Nominally, the free movement of the adjusting end of the strap is accomplished by disengagement of the lip, as shown in Rehm and Hastings, from the free end of the strap to such an extent that its frictional resistance with the adjacent portion of the strap falls below a predetermined limit and movement of the strap occurs. Additionally, most of the prior art buckles are metallic in nature and subject to corrosion when used in a moist or salt water type of atmosphere.